Field of Invention
The present invention relates to a package and method of manufacturing the same. More particularly, the present invention relates to a chip package and method of manufacturing the same.
Description of Related Art
Digital camera requires the function of image sensing, and digital camera is integrated into portable devices, for example, tablet, smart phones and laptops. CMOS image sensor (CIS) is widely used as an essential component in the digital camera. Photo diode is the foundation of CIS chip package. When light strikes the photo diode, an electronic current is generated which is in positive correlation with the number of photons. A voltage signal, which reflects the number of photons in a given time, can then be generated. This signal is converted to digital signal and output through the circuit of the abovementioned device.
An early development of the CIS chip package is a front side illuminated (FSI) sensing system. However, in the front side illuminated CIS device, the incident photons have to pass through a metal layer and a dielectric layer to arrive at the photo diode, and the quantum efficiency may be compromised because the incident photons are absorbed or scatter randomly before they arrive at the photo diode. Hence, back side illuminated (BSI) CIS is developed to overcome this issue. The back side illuminated CIS chip package receives light from the back of the semiconductor substrate. The light path is relatively short and it does not need to go through the metal layer and the dielectric layer or other intermediate layers. Thus, the incident photons will not be absorbed or scatter before they arrive the photo diode, and a higher quantum efficiency can be satisfied. The back side illuminated CIS chip package is commonly used in electronic devices.
However, many difficulties remain in the manufacturing of the back side illuminated CIS chip package, especially the high production cost, thicker profile. An urgent need is calling to provide a new structure and method so as to tackle the problems.